/**
 * Copyright (C) 2012 Oleg Anastassov <o.anastasov@gmail.com>
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package kz.kstu.ent.util;

import java.text.DecimalFormat;
import java.text.ParseException;

/**
 * @author Oleg Anastassov
 */
public final class NumberUtil {

    public static final String DECIMAL_FORMAT_PATTERN = "##.00";
    public static final DecimalFormat DECIMAL_FORMAT = new DecimalFormat(DECIMAL_FORMAT_PATTERN);

    private NumberUtil() {
    }

    public static Integer parseInt(String s) {
        if (!StringUtil.isEmptyOrNullString(s)) {
            return Integer.parseInt(s);
        } else {
            return null;
        }
    }

    public static Long parseLong(String s) {
        if (!StringUtil.isEmptyOrNullString(s)) {
            return Long.parseLong(s);
        } else {
            return null;
        }
    }

    public static Double parseDouble(String s) {
        if (!StringUtil.isEmptyOrNullString(s)) {
            try {
                DecimalFormat format = (DecimalFormat) DecimalFormat.getInstance();
                Number number = format.parse(s);
                return number.doubleValue();
            } catch (ParseException e) {
                throw new NumberFormatException("NumberFormatException: " + s);
            }
        } else {
            return null;
        }
    }

    public static String formatDouble(Double number) {
        if (number == null) {
            return StringUtil.EMPTY_STRING;
        }
        DecimalFormat format = new DecimalFormat(DECIMAL_FORMAT_PATTERN);
        return format.format(number);
    }
}
